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Iznogood
Asked: 2011-02-16 08:20:28 +0800 CST

Detecting raid setup in centos 5

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We have bougth a server off of Iweb web hosting and its supposed to have raid5 hardware installed. At this point so many things have gone wrong with IWeb we are just not sure we have our raid at all.

From ssh is there any command I could use to see what kind of raid we have setup?

Seems like mdadm is not installed and none of the other I have found.

df -h gives:

Filesystem            Size  Used Avail Use% Mounted on
/dev/sda5             1.8T  4.3G  1.7T   1% /
/dev/sda2             2.0G   36M  1.9G   2% /tmp
/dev/sda1              99M   12M   82M  13% /boot
tmpfs                 5.9G     0  5.9G   0% /dev/shm
tmpfs                 5.9G     0  5.9G   0% /usr/local/psa/handlers/before-local
tmpfs                 5.9G     0  5.9G   0% /usr/local/psa/handlers/before-queue
tmpfs                 5.9G     0  5.9G   0% /usr/local/psa/handlers/before-remote
tmpfs                 5.9G     0  5.9G   0% /usr/local/psa/handlers/info
tmpfs                 5.9G  4.0K  5.9G   1% /usr/local/psa/handlers/spool
linux centos raid5

5 Answers

  1. Best Answer

    See: How to find RAID configuration/level and RPM speed having only remote access to the server?

    Depending on the server hardware, you can try a couple of things to find the config. Start with dmidecode piped into less to obtain the server make/model information (and potentially, the serial number). For Dell, dmidecode | grep -i serial should output the service tag. You can cross reference the initial build info from Dell's support site.

    For Dell and most hardware raid controllers, cat /proc/scsi/scsi should reveal the SCSI controller and/or RAID controller config.

    Attached devices:
Host: scsi0 Channel: 00 Id: 00 Lun: 00
  Vendor: TEAC     Model: DVD-ROM DV-28SW  Rev: R.2A
  Type:   CD-ROM                           ANSI  SCSI revision: 05
Host: scsi2 Channel: 00 Id: 00 Lun: 00
  Vendor: SEAGATE  Model: ST9146803SS      Rev: FS62
  Type:   Direct-Access                    ANSI  SCSI revision: 05
Host: scsi2 Channel: 00 Id: 01 Lun: 00
  Vendor: SEAGATE  Model: ST9146803SS      Rev: FS62
  Type:   Direct-Access                    ANSI  SCSI revision: 05
Host: scsi2 Channel: 01 Id: 00 Lun: 00
  Vendor: Dell     Model: VIRTUAL DISK     Rev: 1028
  Type:   Direct-Access                    ANSI  SCSI revision: 05

    Armed with the drive model numbers, you can google to obtain the specifications. The last entry in the output clearly shows a virtual disk comprised of the two physical disks listed above. You can get the exact controller spec from lspci -v.

    • 4

  2. mdadm is not needed if you really have hardware raid, as the OS should only see one device for every raid array in the system.

    One way to detect an hardware raid controller could be to scan your boot.msg log file for scsi devices that identify themselves as RAID controllers. I.e. I have a system with a 3ware controller and find the following lines in my kernel boot log: 

    <6>3w-9xxx 0000:03:00.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16
<7>3w-9xxx 0000:03:00.0: setting latency timer to 64
<6>scsi2 : 3ware 9000 Storage Controller
<4>3w-9xxx: scsi2: Found a 3ware 9000 Storage Controller at 0xba900000, IRQ: 16.
<4>3w-9xxx: scsi2: Firmware FE9X 3.08.00.016, BIOS BE9X 3.08.00.004, Ports: 16.
<5>scsi 2:0:0:0: Direct-Access     AMCC     9650SE-16M DISK  3.08 PQ: 0 ANSI: 5
    • 3

  3. If this is a virtual server of some form then no, there's no way you can know what's actually servicing your disk IO. If it's a physical server you may be able to install (or find if already installed) any disk controller tools/diags code that would be able to tell you what the disk layout is. There's certainly nothing in the 'df' you provided that would point one way or another. Ultimately it's a question best asked of them, if you get more details from them feel free to come back here and we'll see what we can do ok.

    • 2

  4. Try using lspci to determine if there is a hardware RAID controller. If there is a hardware controller the OS will not normally be able to see the RAID using the normal tools, however there are normally Linux based clients available for the big vendors (PECL/3com/etc).

    Another useful tool to see lowlevel hardware is dmidecode. It can tell you a lot about the physical box your using.

    • 2

  5. mdadm is for Linux software RAID. Try probing the hardware with dmidecode to determine the hardware vendor for the RAID controller. From there, you will need to use the vendor specific utility to query the RAID controller for it's configuration.

    See this question for more information: Is it possible to get an inventory of all physical hard disks on a linux server?

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